docs: add Sphinx documentation build and deploy workflow

- Add Gitea Actions workflow to build and deploy docs on push to main
- Generate Sphinx reference documentation for all apps and modules
- Deploy versioned and latest docs via rsync over SSH

docs/source/reference/apps/library/library.api.rst

@@ -0,0 +1,18 @@
+library.api package
+===================
+
+.. automodule:: library.api
+   :members:
+   :show-inheritance:
+   :undoc-members:
+
+Submodules
+----------
+
+.. toctree::
+   :maxdepth: 4
+
+   library.api.serializers
+   library.api.urls
+   library.api.views
+   library.api.workspaces